Firstly let me say I've never played PS before, so don't know much about it. What I do know, and about PS2, is through interviews, videos, veterans accounts and all the good stuff like that.
Second, about your post, few things:
1) You come to a site that is well known in the gaming market and community, who are not only big but have their own community... so obviously have guilds, clans, groups, squads etc associated with PCG of their own.
2) The "For arranging community games and guilds"... part is for the games and guilds set up with, by and for PCG, not outsiders.
3) If you have 300+ members, why come here anyway?
4) This one I'm unsure about, but from what I've gathered this game isn't really so much as a casual experience. It's a large-scale MMOFPS concentrating on territorial control in an open-world with thousands of players. I don't think, and vets please correct me if I'm wrong, you can be casual when playing this.